1. Field of the Invention
The present invention relates to an iris recognition method for effectively and accurately detecting iris from a captured eye image although the eye is covered by an eyebrow or an eyelid in the captured image, and an apparatus thereof.
2. Description of the Related Art
Among various biometric methods, iris recognition has been known as an excellent method for identifying a person in a view of uniqueness, invariability, and stability. The iris recognition has been applied to various fields requiring high level security because the false recognition rate of the iris recognition is very low.
Human's iris is fully grown up before three years old, and it does not change for life time unless he or she has specific trauma. Since the iris has more various patterns than a fingerprint patterns, it is known as the perfect personal identification method. Since the image of iris can be obtained in non-contact manner, it is very convenient personal identification method in a view of a user. Therefore, it is expected that the iris recognition will occupy a large portion of related market.
In general, it is essential to quickly recognize a pupil and iris from data of an image of persons in a personal identification method using iris recognition. An iris recognition system detects iris image data, specializes the detected iris image data, searches data identical to the specialized data in a database, identifies a person through comparing them, and determines whether it will accept or refuse a related request.
One of methods of obtaining specialized data from iris region was introduced in U.S. Pat. No. 5,291,560 by John G. Daugman. In this conventional method, an iris region is defined by setting one circle close to a boundary between an iris and a pupil, setting another circle close to a boundary between an iris and a papillary membrane, and defining an area between two set circles as the iris region. Then, the iris region is equally divided by a plurality of concentric circles, and annulus selection regions are defined. Then, iris feature data is extracted from each of the annulus selection regions through Gabor transform, and extracted iris feature data is stored as iris codes, thereby building a database. After building the database of the iris codes, iris feature data extracted from personal iris recognition is compared with each selection region of a registered iris feature data. It determines that a person requesting authentication is an identical person with a registered person if the difference is smaller than a predetermined threshold value.
Another conventional method was introduced in Korea Patent No. 10-0376415 that teaches a method of calculating a center point of an iris by obtaining both end points of boundaries in a horizontal direction and a vertical direction in a pupil area from a binary image, and calculating a middle point of obtained two end points as the center point of an iris.
In this method, it is difficult to recognize the iris if an eye is covered by an eyebrow or an eyelid. Therefore, there is demand for a method of effectively and accurately detecting iris from a captured eye image although the eye in the captured image is covered by an eyebrow or an eyelid in order to improve the iris recognition.